COLUMBUS(WCMH/AP) — The FBI says dozens of pimps, prostitutes and associates have been arrested under international efforts to combat underage human trafficking.

The FBI says 239 child-sex traffickers and their associates were arrested and 82 children were rescued from Oct. 13 to 16 as part of Operation Cross Country X.

This is a depressing day in law enforcement,” said FBI Director Comey, “because this is the world we live in and the work we have to do.” But it is also a proud day for law enforcement, he added, “because there are people who spend every day worrying about how to rescue these children. They are true heroes.”

Among the 82 juveniles recovered during the three day operation were two sisters in Milwaukee, ages 16 and 17, who told authorities that their mother was their pimp, the FBI said in a news release. The girls said their mother also rented out their brother’s room to a registered sex offender.

Operation Cross Country is part of the FBI’s Innocence Lost National Initiative. Since its creation in 2003, the program has resulted in the identification and recovery of more than 6,000 children from child sex trafficking.

“Operation Cross Country aims to shine a spotlight into the darkest corners of our society that seeks to prey on the most vulnerable of our population,” said FBI Director Comey. “We are not only looking to root out those who engage in the trafficking of minors, but through our Office for Victim Assistance, we offer a lifeline to minors to help them escape from a virtual prison no person ever deserves.”